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Reading multiple variables in a loop


 
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# 1  
Reading multiple variables in a loop

Hi,

I managed to read and print variable as shown in the below code.

Code:
table_name=table1,table2,table3

i=0
IFS=","
for i in $table_name
do

        echo $i

done

Is there a way how I can read more than one variable. For example I need to read 2 variables and populate the output as shown below


table_name=table1,table2,table3
col_name=col1,col2,col3

Output:
table1 col1
table2 col2
table3 col3


Thanks
# 2  
Quote:
Originally Posted by shash
Is there a way how I can read more than one variable. For example I need to read 2 variables and populate the output as shown below
Yes, there is. But in fact there is a better (and MUCH better readable) way to accomplish this if you use arrays - a feature almost every modern shell offers:

Code:
#! /bin/ksh

table[1]="table1" ; col[1]="col1"
table[2]="table2" ; col[2]="col2"
table[3]="table3" ; col[3]="col3"
table[4]="table4" ; col[4]="col4"

counter=1

while [ $counter -le ${#table[@]} ] ; do
     echo "TABLE: ${table[$counter]}     COL: ${col[$counter]}"
     (( counter += 1 ))
done

${#arrayname[@]} is an automatically maintained integer giving the number of elements in the array arrayname.

I hope this helps.

bakunin
This User Gave Thanks to bakunin For This Post:
# 3  
Thanks bakunin. The issue is the variable will be in the following format:

Code:
table_name=table1,table2,table3
col_name=col1,col2,col3

In this case how to use the array please?
# 4  
You might try sth. along this line (tested in bash):
Code:
OI="$IFS"
IFS=,
table_arr=($table_name)
col_arr=($col_name)
IFS="$OI"

This User Gave Thanks to RudiC For This Post:
# 5  
Many thanks Rudi & bakunin. Got it working as follows:
Code:
table_name=table1,table2,table3
col_name=col1,col2,col3

OI="$IFS"
IFS=,
table_arr=($table_name)
col_arr=($col_name)
IFS="$OI"

counter=0

while [ $counter -lt ${#table_arr[@]} ] ; do
     echo "TABLE: ${table_arr[$counter]}     COL: ${col_arr[$counter]}"
     (( counter += 1 ))
done

# 6  
Quote:
Originally Posted by shash
Thanks bakunin. The issue is the variable will be in the following format:
Why? If it is a variable you can define it in any way you want, no?

Or is it some external input you need to use? In this case: how did it get into this variable? Perhaps there is a better way to put it in more suitably formed variables. You might want to present the whole problem, not just an arbitrary part of it.

Quote:
Originally Posted by shash
Code:
table_name=table1,table2,table3
col_name=col1,col2,col3

In this case how to use the array please?
The following is not pretty and less readable than my original idea, but there you go:

Code:
#! /bin/ksh

table_name="table1,table2,table3"
col_name=col1,col2,col3
table=""
col=""

while [ "$table_name" != "" ] ; do
     table="${table_name%%,*}"
     col="${col_name%%,*}"

     echo "TABLE: $table    COL: $col"

     table_name="${table_name##${table}}"
     col_name="${col_name##${col}}"
     table_name="${table_name##,}"
     col_name="${col_name##,}"
done

I hope this helps.

bakunin
This User Gave Thanks to bakunin For This Post:
# 7  
I 'm reading it from a global variable which I can't change. I need to read those variables as I had mentioned. Many thanks for your help.
 

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